Zero magnetostriction in amorphous Co-M-Nb alloys with high saturation magnetization

We have examined the dependence of magnetic properties of sputter-deposited amorphous Co-M-Nb alloys upon concentration of M (M = Mn, Fe, Ni, Ti and Mo). Particular interest is directed to the changes in saturation magnetization and magnetostriction (λ
s
) of these alloys. It has been found that λ
s
in amorphous Co alloys with non-magnetic metals (Ti, Zr, Nb etc.) varies from positive to negative values through zero λ
s
as decreasing the atomic size of these metals. This behaviour is quite different from that of amorphous Co alloys with metalloids, in which λ
s
is always negative and insensitive to the kind of the metalloids Concerning the concentration trend, it is noted that the values of λ
s
are almost constant in the wide range of Nb concentration in spite of the large changes of saturation magnetization and the Curie temperature. The addition of Fe and Mn to Co
85
Nb
15
increases the saturation magnetization and meets zero magnetostrictive alloys in (Co
1-x
M
x
)
85
Nb
15
with M = Fe, Mn and x= 0.02 and 0.05, respectively.